Moore faces allegations from nearly 10 women who say he pursued them as teenagers when he was in his 20s and 30s, including multiple women who say he assaulted them.

Tillis originally called for Moore to withdraw from the race and said Thursday that he still stands by that position, but added that until Moore is under the jurisdiction of the Senate, the decision is in the hands of Alabama voters.

"There’s Supreme Court precedent to say that we really don’t have the authority to deny him being seated,” he said. “But we do have jurisdiction over members, and we use an ethics investigation and then we look at what remedies come from that.”

Tillis also criticized colleagues who have stood by Moore on the basis that he will help advance the GOP agenda.

“Anyone that would say, ‘Yeah, he’s got problems but he’s a Republican vote’ really ought to rethink whether or not they should be in this institution,” he said.

Following Trump’s endorsement, the Republican National Committee (RNC) reinstated its support of Moore, giving $170,000 to the Alabama Republican Party to help the campaign, after originally distancing itself from the candidate.

Gardner, the chairman of the Senate GOP's campaign arm, broke with Trump and the RNC on Thursday, saying "we will never" endorse Moore.